SummaryWe previously found that 40% of breast cancer patients showed enhanced sensitivity to X-ray induced chromosome damage in G 2 lymphocytes and suggested that this might indicate a low penetrance predisposition to breast cancer, for which there is good epidemiological evidence. We have now tested the hypothesis that elevated G 2 radiosensitivity is a marker of such predisposition to other common cancers. We tested patients with colorectal cancer, for which there is also good epidemiological evidence of inherited risk in a substantial proportion of cases, and patients with cancers having a strong environmental aetiology (lung and cervix). We also repeated our study of breast cancer cases and tested patients with chronic diseases other than cancer. The results support our hypothesis, in that 30% (12/37) of colorectal cases showed enhanced sensitivity compared with 9% (6/66) of normal healthy controls (P = 0.01), whereas the proportions of sensitive cervix (11%, 3/27, P = 0.72) and lung cancer cases (23%, 8/35, P = 0.07) were not significantly above normals. We confirmed the enhanced sensitivity of 40% (12/31, P = 0.001) of breast cancer patients and found that patients with non-malignant disease had a normal response in the assay (12%, 4/34, P = 0.73). We suggest that enhanced G 2 chromosomal radiosensitivity is a consequence of inherited defects in the ability of cells to process DNA damage from endogenous or exogenous sources, of a type that is mimicked by ionizing radiation, and that such defects predispose to breast and colorectal cancer.

BackgroundWeekly docetaxel has occasionally been used in the neoadjuvant to downstage breast cancer to reduce toxicity and possibly enhance quality of life. However, no studies have compared the standard three weekly regimen to the weekly regimen in terms of quality of life. The primary aim of our study was to compare the effects on QoL of weekly versus 3-weekly sequential neoadjuvant docetaxel. Secondary aims were to determine the clinical and pathological responses, incidence of Breast Conserving Surgery (BCS), Disease Free Survival (DFS) and Overall Survival (OS).MethodsEighty-nine patients receiving four cycles of doxorubicin and cyclophosphamide were randomised to receive twelve cycles of weekly docetaxel (33 mg/m2) or four cycles of 3-weekly docetaxel (100 mg/m2). The Functional Assessment of Cancer Therapy-Breast and psychosocial questionnaires were completed.ResultsAt a median follow-up of 71.5 months, there was no difference in the Trial Outcome Index scores between treatment groups. During weekly docetaxel, patients experienced less constipation, nail problems, neuropathy, tiredness, distress, depressed mood, and unhappiness. There were no differences in overall clinical response (93% vs. 90%), pathological complete response (20% vs. 27%), and breast-conserving surgery (BCS) rates (49% vs. 42%). Disease-free survival and overall survival were similar between treatment groups.ConclusionsWeekly docetaxel is well-tolerated and has less distressing side-effects, without compromising therapeutic responses, Breast Conserving Surgery (BCS) or survival outcomes in the neoadjuvant setting.Trial registrationISRCTN: ISRCTN09184069

The results suggest the possibility that a substantial proportion of early onset cancers are associated with the inheritance of predisposing genes of low penetrance. However, support for this hypothesis requires that the heritability of chromosomal radiosensitivity be demonstrated in family members. In addition, a larger study is now required to investigate the chromosomal radiosensitivity of specific early onset cancers.

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